Superwalnut (or just plain ol' BW)

[smokinj]

Well, my spreadsheets are completed, and I just keep updating figures as I get them. Seems as if this walnut may just be some normal BTU stuff. I'll wait until the measurements and calculations are done before I bore you with tons of numbers,, but I think you'll at least find the moisture content analysis interesting (as always).

Ok educate me here. Just what the heck is a Super bw anyways?

It's something I made up because I was convinced my BW has more BTUs than everybody else's, lol.

I do get some that is awesome. Even the 880 has trouble with it. Burns good and throws sparks.

 

[Danno77]

Well, I did this:

...
...
...
Until it stopped dropping weight and then I tested again to get this:

 

[Chargerman]

I suddenly have the urge for some walnut brownies! ;-)

 

[weatherguy]

The length is not that important I just look for the wide stuff.

Thats what she said

 

[Danno77]

Verdict is in. My walnut isn't super. I intend to determine dry volume again after I get a caliper instead of the stupi ruler I used. Too much room for error. And then multiply the opportunity for error because I measured 7 different pieces instead of one or two big pieces... Anyway, the density may have some room for error, but the moisture numbers should be pretty darn close.

What would you do if your MM read 91%?

 

[REM505]

You ever try just taking the bucking chips from different heights and dry those?

 

[Battenkiller]

Excellent job, Danno! Very intriguing results.

So... if you estimate that there are about 85 cu.ft. of solid wood in a cord, and that the wood is at 20% MCwb when you burn it, that works out to 20,516,573.095683537953245678745670003466 BTU/cord. %-P

'Bout the same as black cherry, as I expected.

P.S. Just busting your stones about the significant figures, but you should only include as many as your least accurate measurement. In this case, round it off to the nearest tenth. Easier on the eye as well.

 

[Danno77]

LoL about the rounding. I used the "Numbers" spreadsheet program on my iPad, and I'm not very proficient at it yet, so I didn't know how to limit the decimals!

Jack Wagon, you mean like the actual sawdust chips? If so, measuring their volume could be difficult. I did, however, consider taking (and still can) a sample from higher up in the tree. This sample was from about chest height.

Another thing I was curious about was the white ring that black walnut has, and whether that was lower or higher BTUs. I've noticed that the broad yard variety has more white (proportionately) than the tall thin timber variety.

 

[smokinj]

Verdict is in. My walnut isn't super. I intend to determine dry volume again after I get a caliper instead of the stupi ruler I used. Too much room for error. And then multiply the opportunity for error because I measured 7 different pieces instead of one or two big pieces... Anyway, the density may have some room for error, but the moisture numbers should be pretty darn close.

What would you do if your MM read 91%?

Throw it in the river.....Then we know the reading! :cheese:

 

[Battenkiller]

Keep those samples out in the living space when you are done with them. You'll be surprised at how much weight they gain just sitting there, even in the dry winter air in the home. Then put them outside in a spot they won't get any precipitation on them. Weigh them in the summer, then let us know if wood stays just as dry once you have it there.

 

[REM505]

LoL about the rounding. I used the "Numbers" spreadsheet program on my iPad, and I'm not very proficient at it yet, so I didn't know how to limit the decimals!

Jack Wagon, you mean like the actual sawdust chips? If so, measuring their volume could be difficult. I did, however, consider taking (and still can) a sample from higher up in the tree. This sample was from about chest height.

Another thing I was curious about was the white ring that black walnut has, and whether that was lower or higher BTUs. I've noticed that the broad yard variety has more white (proportionately) than the tall thin timber variety.

Yes I was meaning the sawdust chips. You would only need about 5-10g in a small aluminum foil boat for percent solids/moisture. Although I think I see your point about volume.

 

[Danno77]

LoL about the rounding. I used the "Numbers" spreadsheet program on my iPad, and I'm not very proficient at it yet, so I didn't know how to limit the decimals!

Jack Wagon, you mean like the actual sawdust chips? If so, measuring their volume could be difficult. I did, however, consider taking (and still can) a sample from higher up in the tree. This sample was from about chest height.

Another thing I was curious about was the white ring that black walnut has, and whether that was lower or higher BTUs. I've noticed that the broad yard variety has more white (proportionately) than the tall thin timber variety.

Yes I was meaning the sawdust chips. You would only need about 5-10g in a small aluminum foil boat for percent solids/moisture. Although I think I see your point about volume.

Gotchya, your method would probably work well for moisture testing and would dry the wood wayyy faster. In fact, I worry about drying it too fast to get a reading. Maybe cut and immediately scoop it into a ziplock or sealed container!

 

[ISeeDeadBTUs]

Awesome looking wood!!

Uh Danno? is there a connection between your having a drug scale and your burning BW for firewood?? ;-P We're doing hardwood cuttings - asexual propagation - this year to try to boost our volume of BW, and you're just seein' BTUs!! :bug:

 

[Battenkiller]

Yes I was meaning the sawdust chips. You would only need about 5-10g in a small aluminum foil boat for percent solids/moisture.

You need a much larger sample size unless your scale is extremely accurate. A digital scale that reads in tenths of a gram may seem extremely accurate, but it rounds up or down to the closest tenth, potentially inducing enough error to throw your results off by several percentage points with a very small sample. As well, the other volatiles in the wood have an easier time evaporating when the wood is in the form of chips. This can give the impression that your wood is wetter than it really is, since the working assumption in this technique is that only water will be driven off.

I use a sample of 1" chunks. I slice several 1" thick pieces along the length with my bandsaw, then split them into small chunks with a special tool scientifically designed for the purpose (a meat cleaver). My total sample size is closer to 200 grams, and I feel that this is sufficient to get the degree of accuracy that I am looking for while still drying quickly.

Of course, Danno was primarily interested in finding the density of his wood to see how many potential BTUs it contained, so the random chunks would have made for some very fancy measuring... even with a Starrett caliper. ;-)

 

[WoodPorn]

Sacrilege....

 

[Danno77]

Yes I was meaning the sawdust chips. You would only need about 5-10g in a small aluminum foil boat for percent solids/moisture.

You need a much larger sample size unless your scale is extremely accurate. A digital scale that reads in tenths of a gram may seem extremely accurate, but it rounds up or down to the closest tenth, potentially inducing enough error to throw your results off by several percentage points with a very small sample. As well, the other volatiles in the wood have an easier time evaporating when the wood is in the form of chips. This can give the impression that your wood is wetter than it really is, since the working assumption in this technique is that only water will be driven off.

I use a sample of 1" chunks. I slice several 1" thick pieces along the length with my bandsaw, then split them into small chunks with a special tool scientifically designed for the purpose (a meat cleaver). My total sample size is closer to 200 grams, and I feel that this is sufficient to get the degree of accuracy that I am looking for while still drying quickly.

Of course, Danno was primarily interested in finding the density of his wood to see how many potential BTUs it contained, so the random chunks would have made for some very fancy measuring... even with a Starrett caliper. ;-)

I really wasn't keen on the small chunks for my density figures, ESPECIALLY considering that I measured all of the pieces with a ruler! If I had a beaker or something a displacement test is what I'd rather have done. My method for determining volume was just about the weirdest thing I could think of, too. I measured all four edges for each direction and then took the average L,W, and H. I was hoping it would be a better measurement because my pieces certainly were not perfectly cut.

 

[REM505]

Yes I was meaning the sawdust chips. You would only need about 5-10g in a small aluminum foil boat for percent solids/moisture.

You need a much larger sample size unless your scale is extremely accurate. A digital scale that reads in tenths of a gram may seem extremely accurate, but it rounds up or down to the closest tenth, potentially inducing enough error to throw your results off by several percentage points with a very small sample. As well, the other volatiles in the wood have an easier time evaporating when the wood is in the form of chips. This can give the impression that your wood is wetter than it really is, since the working assumption in this technique is that only water will be driven off.

I use a sample of 1" chunks. I slice several 1" thick pieces along the length with my bandsaw, then split them into small chunks with a special tool scientifically designed for the purpose (a meat cleaver). My total sample size is closer to 200 grams, and I feel that this is sufficient to get the degree of accuracy that I am looking for while still drying quickly.

Of course, Danno was primarily interested in finding the density of his wood to see how many potential BTUs it contained, so the random chunks would have made for some very fancy measuring... even with a Starrett caliper. ;-)

Yes while it was clear in my head that a larger sampling size would be needed. I think it looked like I was saying a single sample.
Volatiles mass will be lost whether chips or chunks. They will be driven off well before the water. It may be easier to lose volatiles with a larger surface area however there is the problem of retaining water with a sample of equivalent mass and lesser surface area. Depending on the size and density of a chunk of wood there is the possibility of drying the outside while leaving the inner part of the chunk "wet".

 

[Thistle]

Awesome looking wood!!

Uh Danno? is there a connection between your having a drug scale and your burning BW for firewood?? ;-P We're doing hardwood cuttings - asexual propagation - this year to try to boost our volume of BW, and you're just seein' BTUs!! :bug:

lol I quit having a need for any scales other than a big one in the bathroom over 20 yrs ago.

 

[Battenkiller]

Yes while it was clear in my head that a larger sampling size would be needed. I think it looked like I was saying a single sample.
Volatiles mass will be lost whether chips or chunks. They will be driven off well before the water. It may be easier to lose volatiles with a larger surface area however there is the problem of retaining water with a sample of equivalent mass and lesser surface area. Depending on the size and density of a chunk of wood there is the possibility of drying the outside while leaving the inner part of the chunk "wet".

I found this article while avoiding helping my wife pack up her glass shop. It addresses all of the issues you brought up.


(broken link removed to http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/5190/Moisture_Content_ocr.pdf;jsessionid=D92E7DDE11355DA0B69627A9B6ADB50E?sequence=1)


For a 5 gr sample, the scale should be able to accurately read in 5 mg increments. Danno's scale is only readable in 100 mg increments. The article explains why in the text:

In general, the scale should read to 1 part in 1000 for the oven-dry weight of the sample to give accuracy to the nearest 0.1% moisture content. This should be adequate for any mill measurement and, in fact, is as accurate as we ever try to get at the university. So, if the oven-dry sample weight will always be more than 1000 g (2.2 Ibs), the a scale that reads to 1 gram is very adequate.

True, you can take a large number of small samples and average them. Statistically, the round ups should be close to the round downs if the quantity of samples is large enough, but nothing will be as accurate as just using a sample weight that matches the range and accuracy of the scale being used.


They also show a couple of examples where both the oven-dry method and the desiccation method were used on shavings, and there were large errors with the oven-dry method on shavings.

Since there was no pattern to the data, about the only conclusion we can make is that the oven dry method may at times drive volatile compounds out of samples and therefore cause too high of a moisture content to be calculated. This is probably not as much of a problem with lumber samples since they are many times thicker than shavings.

It is a good article that explains the reason why wood dries. It is all about relative humidity. Even in an oven, wood can fail to dry to completion if there is enough humidity in the air to raise the RH inside the oven to above 0%. And no matter how hot your wood gets in the sun, or how windy your location is, if the average RH in your area is above a certain amount, no amount of heat and wind can ever bring it down below the EMC associated with that RH.


They even touch on one of the most hotly debated topics in firewood:

Oregon white oak was being dried in a small kiln near Corvallis. The kiln operators were having trouble believing that it could dry so slowly.

;-P


And to further confuse us all, they introduce yet another basis by which to express MC in wood - bone-dry basis. Apparently, bone-dry is the oven-dry weight divided by the green weight. Rest assured, I will not be expressing MC here at any time in the future using MCbdb. :lol:


Bottom line is that no method is 100% accurate, but the standard method (as outlined in ASTM D4442) of weighing a chuck of wood, drying it in an oven until it stops losing weight, and then calculating the final MC by using a specific formula that uses both weights, is probably the very best way to determine if your firewood is down to 20% MCwb.